Oooh I lpve these kinda topics.
I'm afraid lots of people are not gonna like my plans. But since the question is what
I would do I need to be honest.
Like others here I'd propose a series of 13 one-hour life action episodes per season and I would go for a BSG-style "hard" reboot, playing lose with established characters and setting details, drawing from all of Star Trek lore (though no Borg, we had enough of them for a while)
Keep: The basic premise, the time period, Klingons, Romulans and Tholians as adversaries. The idea of Enterprise being away from home for 5 years. There would be a Captain Kirk, a Spock, a Uhura, a McCoy and a Scotty, though they might be different from the characters in the 60s version.
Drop:
1) Sulu and Chekov. Both characters are just kind of redundant since we already have enough human males and I don't see why the navigator and the helmsman should be separate. Also "Sulu" is not a Japanese name, that might have flown in the 60s, but today.....eh....
2) The super-powerul, we are as amoebas antagonists that cropped up sometimes.
3)T he everybody laughes ending, unless there is actually a good reason to celebrate.
4) The "planet of hats" plots. No planets fashioned after 1930s mobsters, Nazis, Cowboys etc.
Change:
1) Change from an episodic nature to multiple, on-going storylines, less to no "filler" episodes multiple points of view (the Enterprise, a Klingn Ship etc.) Strong continuity between episodes. All characters have a relevance to the plot, their own agendas and prominence in different storylines.
2) All the characters get re-interpreted to make them more complex, this doesn't mean they need to have heaps of moral ambiguity or cynicism injected into them, just make them seem less archetypical and more like real people:
Kirk: Has just taken over command of the Enterprise, after the last Captain has been killed in an ambush by the Romulans. Enterprise is his first command and he's still fairly green behind the ears. Is married to Carol Marcus and aware of his young son, David, but his family had to stay behind on Earth, because it's not the 24th century and "take your kids along for the ride" isn't a thing yet. He'd be a romantic, an idealist.
Spock: Would need the least changes. He was not only the most popular character in TOS (and ST) but he was also the best written one in the original series. So the changes would just amount to 1) make him a bit younger 2) get rid of the bowl cut 3) Write him like Spock, but even more so; really drive the point home about this idnividual caught between two cultures, two philosophies, two natures and give him a deep, almost religious thirst for transcendence. To heighten the tensions with his family I'd add Saavik as a rebellious younger sister who years ago fled Vulcan and has severed all ties with her family.
McCoy: Would be replaced by his daughter Joanna. Leonard McCoy would have gone missing in action about 20 years before the show started while he was on a secret mission to bring medical supplies to the Klingon-occupied world of Bajor. A Vulcan vessel received McCoy's request for aid, but chose against action in order to prevent further escalation of the situation. Joanna is a bras young woman with an attitude that can be off-putting and, in the beginning butts heads with Spock because of her resentment for Vulcans. Still her main motivation would be compassion. If she sees people in need she will go help them, no matter the consequences. She would also hope to be reunited with her father one day. As an actress I think Liza Weil
http://en.wikipedia.org/wiki/Liza_Weil would fit my mental picture of her, at least physically.
Uhura: Gets a first name. Possibly Nyota, possibly Nichelle, possibly Upenda. She'd be changed to security chief/tactical officer and be a highly decorated, pragmatic veteran of the Klingon Wars who initially has problems accepting Kirk's authority as a Captain.
"Scotty": Not actually Scottish, also a veteran of the Klingon Wars, he was badly wounded and was rebuilt as a cyborg, a process which replaced about 50% of his brain with a computer. His dilemma would be whether he is still the same man he was before the war and "Scotty" would be a designation he uses in order to distance himself from his human life and possibly based on the designation of the robot brain in his skull. While Uhura would be the "proud veteran" he would be the "wounded" one.
3) The ship's interior and the uniforms would need to be redesigned completely. No mini-dresses and go-go boots. No bright primaries. I'm actually partial to the Enterprise suits or something else more military looking.
4) Klingons get the post TMP look, or better yet the ID look (though possibly with hair). No shoe-cream slathered Foo-Manchus in this version. Int heir behaviour they might get mixed with Cardassians in some ways.
Add:
1) A number of additional (main) characters:
Lt. Ilia: A Deltan telepath of considerable power. Able to read minds, project her thoughts and mind-link with others. She'd be assigned to the Enterprise to provide means to combat Romulan cloaking devices (her telepathy would still be able to sense their life signs with some difficulty) Inistially she would be distrusted by the crew because telepaths are rare in Federation space and closely watched by the authorities. I think she and Scotty, both outsiders, could develop a relationship.
Lt. M'Ress: This young Caitian takes Uhura's original place on OPS. The heart and soul of the crew, everybody's friend she'd also be the first to accept Ilia into the fold. She'd often be underestimated because of her playful cat-like character but in truth she'd be very intelligent when it comes to reading, and manipulating, others.
Ensign Xonsulu: Replaces both Chekov and Zulu as Helmsman/Navigator (I see no point in keeping them separate). A member of a species that has only recently joined the Federation and a member of the first generation of that species to venture into space. Very much a naive country boy who'd have to learn to cope with the stresses and strangeness of space.
2) A bunch of interesting side and recurring characters such as: Carol Marcus, David Marcus, Saavik, Nurse Christian Chapel, Mudd Herron (A Bajoran smuggler who claims to be Joanna's half-brother), Valeris (a Romulan resistance fighter/defector) etc.